The invention relates to endoscope-type devices that may be manually formed and fixed in a particular shape prior to insertion into the area to be examined.
Endoscope-type devices are used in many different fields of application, such as medicine, for example endoscopy, but also in engineering, for example as endoscope-type tools with an endoscope-type, flexible and formable shaft, and in general fields of application such as the controlled movement of extremities, particularly human extremities.
Intubation is the introduction of a tube (or a catheter) consisting of rubber or plastic material into the larynx and then into the trachea of the individual. It serves to maintain an effective exchange of gases, which is essential for providing organs with oxygen, among other things, and which is usually effected by respiration. In situations in which the patient is not capable of breathing himself as a result of an illness, an injury or medication, for example when a narcosis is carried out, artificial respiration has to be carried out. A prerequisite for this artificial respiration is a secure connection between the respirator and the patient""s respiratory tract. In order to ensure that air is supplied to the respiratory organs only, without any air reaching the digestive tract via the esophagus, the tube is pushed with its distal end into the trachea via the mouth or the nose and is positioned there in such a way that both lobes of the lung are aerated. At the proximal end, the tube is connected with the tube system of the respirator via a standardized projection (connector).
If the tip of the tube is not positioned in the trachea, the lobes of the lung are not aerated. In this case, the blood flowing through the lung is not enriched with oxygen to a sufficient extent, and the organs are not provided with oxygen. Depending on how long the organs are not supplied with oxygen to a sufficient extent, apart from the complete restoration of all bodily functions, permanent cerebral injuries (such as a coma) or even death because of cardiac arrest might be possible. Faulty intubation, meaning those maneuvers of intubation in which the tube is not positioned correctly and the tip of the tube rests in the esophagus instead of the trachea, for example, will have the same consequences.
There are several methods and shapes of tubes to ensure secure positioning of the tip of the tube. With patients for whom no special anatomic or pathological conditions are to be taken into account, intubation is usually easy and fast to carry out with the usual methods, mainly the laryngoscopical intubation. However, difficulties may arise if there are pathological changes or anatomic peculiarities; in this case, the patient, who is not breathing, is subjected to artificial respiration by applying a combination of laryngoscopical intubation and fiber-optical intubation or by using devices employed specifically for this purpose.
In emergency intubation, which usually means the intubation of a person who has become unconscious and whose lung is liable to fill with water, it is necessary to supply air from outside as soon as possible in order to minimize the risk of lung injury.
In an emergency situation, that is, at the site of the accident and usually not in a hospital, this is done by means of laryngoscopical intubation; here, using a laryngoscope, lifting the tongue root and the epiglottis, the patient""s pharynx is opened in order to gain a good view on the entrance to the larynx, the rima glottidis. If the rima glottidis is only partially visible, it is difficult to introduce the tube. One manages by changing the shape of the tube in its longitudinal axis until the tip of the tube can securely reach the entrance to the trachea. Prior to the present invention, changing the shape of the tube has been done by internally splinting the tube by means of a guide rod in the form of a flexible wire sheathed with plastic material which is inserted therein, which is so stable after bending that it transfers its shape in the longitudinal axis to the elastic tube. It is displaceable in the longitudinal axis within the tube, so it may also project from the distal tube end with its soft tip. Depending on the anatomic conditions, the guide rod is bent in such a way that its tip can be pushed through the rima glottidis and the tip of the tube can then be positioned in the trachea by sliding it over the guide rod. If the rima glottidis is not visible because of anatomic difficulties, so the path of the tube or the guide rod cannot be watched when it is pushed forward, there is a higher risk of injuries and a markedly reduced hitting accuracy. Although there are special instruments which are to make it possible to see the rima glottidis even under difficult conditions, the view through the tube is often obstructed when they are used because of the narrow conditions. For this reason, in difficult cases, the application of laryngoscopical intubation is not favorable.
Therefore, in these cases, fiber-optical intubation is preferably applied, in which an endoscope is used in order to find the entrance to the trachea and to illuminate and make visible the area to be inspected. Furthermore, by means of a mechanism mounted on the holding portion of the endoscope, the position of the tip of the endoscope can be changed, and it can therefore be visibly pushed through the rima glottidis. The tube previously placed upon the tube of the endoscope is then pushed forward as far as into the trachea; then, the endoscope is pulled out of the tube which has been positioned correctly, and the tube is fixed to the patient""s head and is connected with the respirator.
However, the fiber-optical method cannot be carried out optimally in all cases, either. It is particularly difficult if the patient is lying on his back and his musculature is slackened, because the tongue root falls back, thus blocking the path to the trachea. Furthermore, as one hand is required to guide the endoscopexe2x80x94usually by means of the surrounding tubexe2x80x94in fiber-optical intubation and a second hand is required to operate the mechanism of the endoscope, another person is necessary to lift the tongue root by means of a laryngoscope; however, such a person is not necessarily present in case of an emergency.
In the document EP 0 742 026 A, a flexible and simultaneously formable endoscope with a viewing lens was therefore suggested, over which a tube can be slid. Here, formability and flexibility was to be obtained by an articulated rod whose individual adjacent links with convex or concave surfaces could be tensed by tensional or compressive forces. What was disadvantageous, however, was that tests during manufacturing revealed that this principle is very complex because of the frictional forces which are difficult to control and that sufficient flexibility with simultaneously adjustable stiffness cannot be realized with this endoscope.
It is an object of the present invention to provide an endoscope-type device at low cost and in a simple manner, which overcomes the above-mentioned drawbacks and which includes a formable and stiff shaft which, after releasing, changes into a flexible condition at least in partial areas.
According to the invention by arranging longitudinal bendable pulling and/or pushing elements or their distal ends at the shaft at different distances from the proximal end, the shaft can manually be brought into a desired shape in the flexible, that is, non-fixed condition, which becomes stiff by locking the pulling and/or pushing elements. Here, the pulling and/or pushing elements, which are limited at least in the pushing or pulling direction, act on the shaft, and the stability of the stiffness can be increased by a bilateral limitation. In spite of the fact that a pre-formed shape of the shaft has been locked, the introduction is made easier by the controllable tip of the endoscope, particularly in extreme situations or for physicians with less experience, because when introducing the device into the tracheaxe2x80x94for example in case of an emergency intubationxe2x80x94the respective next section of the path ahead can be watched via the lens and the tip can be adjusted to the respective curves. As a result, for example even in case of rupture of the trachea, it is possible to compensate the existing displacement of the trachea ends (which might be several millimeters) at the point of rupture by moving the tip correspondingly and to guarantee an easy and fast introduction of a tube or a trachea catheter (slid over the shaft), even past such an extreme position.
In an advantageous embodiment of the invention, the tip of the device is controllable in only one plane to be moved up and down or to the left and to the right; advantageously, this movement can already be achieved with a small number of control means and the cross-section of the shaft within which the control means are housed can be maintained correspondingly small.
By rotating the entire device about its longitudinal axis, however, arbitrary directions or head positions can be reached, with such a rotation being possible in a specific range without causing an injury to the trachea even in case of emergency intubation. Of course, with corresponding dimensions, it is also conceivable to arrange further control means in the shaft up to the tip so that it is made possible to control the tip of the device in all directions, as is the case with conventional flexible endoscopes. As, in the preferred embodiment of the invention, the movability and formability may be limited to a movement within the same plane including the longitudinal axis of the device, too (for example, an S-shaped movement), as is the case with the controllability of the tip, the rigidity in other planes and thus the resistance to upsetting deformation or distortion is particularly high, especially in case of a rotation about the longitudinal axis of the device. In this case, the entire device constitutes a body which is naturally rigid or strong, thus resisting movements in other directions.
In an embodiment of the invention, the pulling and/or pushing elements, for example steel strands, may be movably received in guide elements at the shaft in the longitudinal direction. Hereby, the stability of the rigidity is advantageously increased, as the path length of the pulling and/or pushing elements is defined exactly by the fact that the guide elements receiving-the pulling and/or pushing elements are fixedly positioned.
In a further embodiment of the invention, seen from a cross-sectional view, the pulling and/or pushing elements are positioned in a ring-shaped arrangement within said shaft (1) at the inner periphery thereof, so their lever action and thus the stability of the rigidity, which increases with increasing distance from the center line, is advantageously improved.
In a further embodiment of the invention, lateral guide means are arranged inside the shaft which, seen in a cross-sectional view, are opposed to each other, and which are fixedly connected with the shaft at least in partial areas. Advantageously, this will prevent undesired bending of the shaft within the plane defined by lateral guide means.
In a further embodiment of the invention, the channel is configured as a channel for an optical light guide and an optical image guide or as a channel for instruments. Advantageously, this makes it possible to check and facilitate the arrival at an aiming point when the endoscope-type device is introduced into a non-visible portion.
In a further embodiment of the invention, pulling and/or pushing elements act on the shaft in pairs in the axial direction, substantially at equal distances from the proximal end. Hereby, as a result of the cooperation of pulling and pushing forces of a pair, stability may be increased. Such pairs of pulling and/or pushing elements may be arranged point-symmetrically at the shaft in order to advantageously exert the optimum stability in a freely movable shaft without any lateral limitation with their maximum distance from each other.
In case of lateral limitation to the movement, however, it may also be advantageous for an optimum effect of the forces to arrange pairs of pulling and/or pushing elements at the shaft to be symmetrical to the horizontal or the vertical axis, in other words: symmetrical to the plane defined by the lateral guide means, respectively.